maybe I wasn't clear , when he hits 100$ to withdraw the 25$ . then grind it up back up to 100 and then move up to 5nl. carry on grinding 5NL til he hits 200$ and withdraw another 25$ then carry on grinding till he hits 300$ withdraw another 25.grind back to 300 and move up to 10NL.
He still gets to move up but builds a contingency fund as he's going so that he wont have to put fresh money in again.